Carroting fur



Patented an it, 1937 aerator cannon Hans 0. Kauiimann, Buffalo, N. Y., assignor to Buflalo Eiectro-Chemioal Company, Inc.

No Drawing Application 23, 1934,

Serial No. 754,541

1% Claims.

it treated to induce the requisite felting properties oi the fur. The procedures whereby the fur, generally rabbit's fur or coney", is rendered suitable-for use in the preparation of felt have been generally designated as carroting. lo, It is generally accepted in the hatting industry that a good felt can be prepared only from fur that has been carroted with mercury nitrate in some form. The mercury carrot as used heretofore is prepared by adding metallic mercury to nitric acid in prescribed proportions, permitting the reaction between the acid and the mercury to proceed to completion diluting with water to g the desired Baum and thereafter brushing the resulting solution upon the fur, permitting the treated fur to dry, and thereafter cutting the fur from the skin and felting the fur into hat forms.

It has been proposed from time to time to em-= ploy non-mercurial carroting solutions for treating fur preparatory to the felting operation: in substantially every case the use or the nonmercurial solutions has been abandoned after a short trial. It wouldappear that proper felting qualities are imparted to the fur by the mercury salt and nitric acid as those carroting solutions in which these materials are constituents. have been the only solutions which have enjoyed any long continued commercial use. 1

Extreme precautions must be observed in the preparation and use of mercury nitrate carrot since the mode of application of the carrot to the fur must be such that the hair or fur is moistened with the solution from the tip to the base, but such moistenlng, usually done by brushing the solution upon the fur, must be done in such manner so as not to apply too great an excess of the carroting solution to the fur, otherwise the hair or fur may be damaged, burnedor discolored, and a with white skins should the discoloration be excessive, the fur is not suitable for the-preparation a carroting solution that can be used to produce fur suitable for use in the preparation of hats in the lighter shades of color. Other advantages of the present invention will become apparent in the following description of the composition and process and will be particularly pointed out in the claims appended hereto.

In the preparation of the carroting composition of the present invention mercury and nitric acid are permitted to react in proportions suiflcient to produce a mercury carrot oi the usual composition, the proportions of nitric acid and mercury being varied over a considerable range, depending upon the type of skin to be treated,

and upon the type of cut iur it is desired to produce. To this solution is added a substance caps ble of removing non-nitric nitrogen compounds, the quantity of the material being 'sumcient to effect the removal of such non-nitric nitrogen compounds that may be present in the solution or that may be developed during the subsequent drying operation to which the skins are subjected after the application of the carrot and which discolor the fur. A mercury carrot of general application is one .of specific gravity of about 13 B.; the amount of the non-nitric nitrogen destroying material added is from about 0.1% to about this quantity generally being sufficient to destroy the nitrogen compounds producing discoloration oi the fur.

Metals having the power of combining with nitric acid and which in contact with the acid fur-cleaning and hydroiyzing agent cooperate therewith to produce properly carroted iur, may be substituted for mercury in the new carrot, due allowance being made for diflerences in their combining weights with respect to mercury. As examples of such metals lead, tin, bismuth and silver may be mentioned as metals whose nitric acid solutions possess the necessary cleaning, hydrolyzing and carroting action upon fur to produce a fur capable of being wetted and ifelted.

The new carrot oi the present invention, therefore, is acid in reaction and contains a metal nitrate with substantially no nitrous acid or lower oxides or nitrogen dissolved in the solution, all the brownish gas being destroyed and the yellowish color, sometimes present in the mercury carrot, being eliminated. The carroting solution, therefore, of the present invention contains an acid hydrolyzing agent for cleaning and modiiying some constitutent substance of crop the fur fiber whereby the fur fiber can be wet when imniersedin hot water, this wetting characteristic not being present to any substantial extent in unsilo vention also contains an added material capable of removing substances present in the usual merquantity sum cient to remove such discoloring agents originally present in the solution, and also those subsequently formed during the hydrolyzing or cleaning action as well as those produced during the drying operation. I have found that color preventing agents are generally reducing agents in the sense that these substances reduce or ren-= 'der inactive the non-nitric nitrogen compounds or other color imparting compounds that may be present in the solution or subsequently formed. during the course 01' the carroting; including the application 01 carrot to the skin and during the drying of the skin with the applied carroting solution upon it.

In carrying out the process of the present invention I preferably apply the carroting solution to the skin by brushing the same into the fur prior to cutting the fur from the skin. The treated skins are stacked and dried and the fur thereafter removed from the skin and e into i'elt. Skins once carroted and dried in accordance with this procedure do not deteriorate but may be kept until it is decided to cut the fur from the skin and tohave it used for felt making.

As a reducing agent or non-nitric nitrogen compound removal agent, I have found hydroxylaminc, in the form of one of its salts, as for instance the sulfate, particularly emcacious; the resulting carrotin'g composition contains a carroting metal nitrate, free nitric acid and the reducing agent to prevent the action of the color imparting materials upon the fur with resultant discoloration thereof.

As a further e'xempliflcation oi the diversity of combination that may be suitably employed," depending upon the type or fur to be treated, the type of fur to be produced, or depending upon manufacturing conditions, temperature conditions employed in the particular manufacturing operation or upon the humidity pertaining within a particular manufacturing plant, the strength and concentration or the carroting solution may be varied over a considerable range.

As illustrative of the range of composition the following are given by way of example:

(i) To 100 parts of a 7 Baum solution of mercury nitrate is added 6 part of hydroxylamine sulphate.

(2) To 100 parts of a 13 Baum mercury ni= trate solution is added 4 parts of hydroxylamine sulphate.

(3) To 100 parts of 20 Baum solution of mercury nitrate is added 12 parts oi'hydroxylamin agent, the quantity of reducing agent in any case being an amount sufllcient to eliminate the material imparting color to the fur during the carroting and subsequent drying. Substances other than hydroxylamine can be employed, and I have found that urea, thio urea, carba-mide and the like may be suitably employed in this connection. Other substances that can be suitably added to prevent the formation of reds and yellows upon the fur are hydrazine as well as certain of its derivatives and also materials or substances recarroted fur." The new carrot oi the present infelts. I

. It will further be seen that the inventionpro acting with the lower oxides of nitrogen, such as ammonia salts, for instance, ammonium chloride. Guanidine also possesses the property of eiim inating the color imparting substances. The preparation of the carroting solution of the present invention is preferably effected with hydroxylamine or other reducing agent not producing the white precipitate within the solution that is formed when hydrazine, urea and some of their derivatives are addedas reducing agents to the mercury nitrate solution.

Examples merely illustrative of the use of other carroting meals and reducing agents are:

(1) To parts of an 8 um lead nitrate solution is added 2 parts of hydroxylae sulfate.

nitrate and a hydrolyzing and cleansing agent acidic in nature, capable of changing the fur fibers from a non-wetting fiber to a fiber capable of being wet with water; the fiber retains its initial and original strength, has not been partially oxidized and destroyed but is readily felted and produces a good shrinking fur. Trie,,-white'. fur carroted in accordance with the process 'oi the present invention is not discolored with-reds and yellows to such an extent that it may not'be used for the production of the lighter vides a carroting composition wherein thei'ur Y coloring agents have been removed from the so lution prior to the application of the carroting composition tothe fur, and a composition possessing, the ability to eliminate any'color impartcarroting composition upon the fur or during the carroted with the composition of the present invention is not burned or rendered harsh and briting substances formed during the action of the tle upon the tips but remains soft and a good feel and possesses good shrinkingqualiso 1. A carroting solution comprising an aqueousmercury nitrate, hydromlamine' and ties necessary for proper tel-1.

at is claimed is:

solution of nitric acid.

2. A carroting solution comprising the reactionproduct of a reducing agent containing an amino.

group and a solution oi mercury nitrate acidin reaction, of at least 3 Baum strength.

3. The process of carroting for which comprises subjecting the fur to the action of an aqueous carroting solution of mercury nitrate, hydroxylamine and nitric acid.

4. The process of carroting fur which comprises subjecting the Iur to the action of an aqueous carroting solution or mercuric nitrate acid in reaction mixed with a reducing agent containing an amino group.

5. A carroting solution comprising an aqueous solution of a carroting metal salt hydroxylamine and nitric acid.

6. A carroting solution comprising an aqueous solution of a carroting metal salt, a reducing agent containing an amino group and nitric acid.

7. A carrotlng solution comprising the reacting product of a reducing agent containing an amino group and a solution of a carroting metal nitrate, acid in reaction, of a. strength of 18 I Baum or less.

8. The process of carroting fur which comprises subjecting the fur to the action of an aqueous oarroting solution of a carroting metal nitrate, a reducing agent containingon amino group and nitric acid.

9. A carroting solution comprising an aqueous solution of lead nitrate, a reducing agent containing an amino group and nitric acid.

10. A carroting solution comprising an aqueous solution of silver nitrate, a. reducing agent con- 5 taming an amino group and nitric acid.

' HANS O. KAUFFMANN. 

